The 17th-century Aslan Pasha Mosque sits in the lower part of the old castle district, with its single white minaret one of the most photographed silhouettes in Ioannina. Built in 1618 on the site of an earlier Orthodox cathedral, it is the best preserved Ottoman religious building in Epirus.
Since 1933 it has housed the Municipal Ethnographic Museum — a small, well-organised collection of Greek, Jewish and Muslim artefacts illustrating Ioannina's three communities before the population exchanges of the 1920s and the Holocaust. The minaret and the prayer hall with its red prayer-niche (mihrab) are open to visitors, and the views from the courtyard over the lake are excellent.